In electronic equipment containing electronic circuits, electronic devices, etc., intrusion of water or dusts from the outside through clearances between the box member and the lid member of the equipment is a problem of giving adverse effects on other component parts of the electronic equipment. Intrusion of water or dusts from the outside can be usually protected by inserting a gasket between the box member and the lid member. However, the insertion of a gasket leads to formation of clearances in the insulator inserted between the box member and the lid member, resulting in a new problem of generating electromagnetic wave leakage through the clearances.
To solve such a problem, gaskets made from electroconductive rubber are often used, but the electroconductive rubber contains electro-conductive materials as a filler, dispersed throughout the rubber, so that the elasticity of the rubber is often deteriorated to lower the gasket durability. It has been also so far proposed to improve the elasticity by complexing. The proposed complexing is based on arrangement of shielding materials on the seal sides of the gasket. Thus, the gasket still has a problem of sealing performance.
Patent Literature 1: JP-A-11-68376
Patent Literature 2: JP-A-11-274793
Patent Literature 3: JP-A-2000-133980